docs: def save(self, *args, **kwargs):
          """ Saves the post instance. """
          new_post = self.pk is None
          super().save(*args, **kwargs)
  
          # Ensures that the subject of the thread corresponds to the one associated
          # with the first post. Do the same with the 'approved' flag.
          if (new_post and self.topic.first_post is None) or self.is_topic_head:
              if self.subject != self.topic.subject or self.approved != self.topic.approved:
                  self.topic.subject = self.subject
                  self.topic.approved = self.approved
  
          # Trigger the topic-level trackers update
          self.topic.update_trackers()